Heineman sent a letter to President Barack Obama confirming that he would allow the controversial, Canada-to-Texas pipeline to proceed through his state.

The project has faced some of its strongest resistance in Nebraska from a coalition of landowners and environmental groups who say it would contaminate the Ogallala aquifer, a massive groundwater supply.

Canadian pipeline developer TransCanada and some workers' unions say the project is safe and will create thousands of jobs.

The original route would have run the pipeline through a region of erodible, grass-covered sand dunes. The new route skirts that area, although the pipeline's most vocal critics remain firmly opposed to it as well.

"Governor Heineman just performed one of the biggest flip-flops that we've in Nebraska political history," said Jane Kleeb, executive director of the group Bold Nebraska.

Heineman said previously that he would oppose any pipeline route through the Sandhills region. In his letter to Obama, he said the new 195-mile route through Nebraska avoids the Sandhills but would still cross part of the aquifer. Heineman said any spills would be localized, and the clean-up responsibilities would fall to TransCanada.

The governor said the project would result in $418.1 million in economic benefits for the state and $16.5 million in taxes from the pipeline construction materials.